Andreas Osterwalder

Affiliation: Ecole Polytechnique Federale de Lausanne (EPFL)

Research Interests: Physics

Title: From cold gas-phase stereodynamics to kinetics at water-water interfaces

Abstract: I will briefly introduce the two primary research directions covered in our group:
A first part will be on experiments to study sub-Kelvin stereodynamics in merged beams. We investigate prototypical energy transfer reactions in the gas phase, namely between metastable Ne(3P2) and other rare gas atoms or small molecules. Such reactions can proceed along two pathways according to       NeX+ + e ̄← Ne(3P2) + X → Ne(1S) +X+ + e ̄       called Penning ionization (producing X+) and associative ionization (producing NeX+), respectively. At high energies the branching ratio between these channels can be controlled through the orientation of the Ne(3P2) atom, but this ability is lost at low energies due to a reorientation of the reactants. In the second part I will be describing our efforts towards studies of gas — liquid water scattering dynamics, for which we cross a molecular beam with a liquid water flat-jet. Liquid flat-jets can be produced by impinging two cylindrical microjets at controlled angles and flow-rates. Such an arrangement produces a series of drop-shaped leaves that provide a flat surface from which gas-phase molecules can be scattered. But, as will be shown, the first leaf in this chain can also serve as a tool to prepare a controlled interface between two liquids, possible miscible, an arrangement that is ideally suited for the study of chemical kinetics at liquid-liquid interfaces.